Propeller hub



June 28, 1932.

s. T. CARTER PROPELLER HUB Filed Nov. 14, 1929 2 Sheets-Sheet 1 June 28, 1932. T CARTER 1,865,170

PROPELLER HUB Jazz/aw wmwm Patented June 28, 1932 UNITED STATES PATENT OFFICE SIDNEY T. CARTER, OF IPARNASSUS, PENNSYLVANIA, ASSIGNOR .TOINTLY T SIDNEY T. CARTER AND ROBERT E. LANKFORD, TRUSTEES, OF PITTSBURGH, PENNSYLVANIA PROPELLER HUB This invention relates to propellers and more particularly to propeller hubs.

An object of the invention is to provide a one-part hub for airplane propellers that shall be of light weight and possess great strength. i Another object of the invention is-to .provide a one-part propeller hub'to which the propeller blades may be rigidly attached.- A further object of the invention is to provide a simplified clamping arrangement for' elecluring the propeller blades to its associated Another object of the invention is to pro- 16 vide a propeller hub from which the pro peller blades may be removed without removing the hub from the engine shaft.

And astill further object of the invention is to provide a propeller hub for airplane pro- .20'pellers that shall be simple in construction,

Fig. 3 is a view in section taken on the line IIIIII of Fig. 2;

Fig. 4 is a front plan view of a modified form of hub construction;

Fig. 5is a top plan view of the modified hub shown in Fig. 4 showing the propeller blades clamped in position and Fig. 6 is a view in section taken on line VIVI of Fig. 4.

Throughout the drawings and the specification like characters of reference indicate like parts.

In Figs. 1, 2 and 3 of the drawings a hub 1 is illustrated which comprises a unitary drop steel forging which is provided with the usual splined sleeve 2 extending transversely therethrough for receiving the shaft of an engine,

not shown. The hub 1 bored out as indi-' cated at 3fto provide a cylindrical or tubular I extension 4 for receiving propeller blades 5 and 6. "As shown the bases; of the propeller blades 5 and 6 are hollowand-of such diameter that they will fit sn1 1gly over the extensions 4. In practice the bases of-the blades 5 and 6' are heated to approximately the temperature of boiling water in order to expand .them sufliciently to facilitate assembling the propeller blades on the extensions 4 of the hub. On coolinga neat fit is obtained between the baseof-the propeller blades and the cylindrical portions or extensions 4 of the hub.

The blades 5 and 6 may be adjusted, as to the pitch angle, with ease because the cylindrical extensions ,4 and the walls of the hollow bases of the blades are straight rather than tapered. Heretofore, it has been the practice to provide a tapered fit between the blades and that portion of the hub to which they are secured. Such construction is objectionable because it is difficult to remove the blades from the hub, and also because it is difficult to adjust the pitch angle.

As shown, the propeller hub 1 is provided with annular or circular flanges 7 and 8 which flanges are tapered as indicated at 9 and 10. Flanges 7 and 8, as illustrated, may be disposed parallel to the longitudinal axis of the hub bore 2 and'concentric with the longitudinal axes of the tubular portions 3.

The propeller'blades 5 and 6 are also provided with annular flanges 11 and 12, respectively, which when in place on the hub, are adjacent to and about the annular flanges 7 and 8 of the hub. The flanges 11 and 12 of the propeller blades are also tapered as indicated at 13 and 14, respectively. It is to be noted that the flanges 11 and 12 of the blades 5 and 6 are of larger diameter than the flanges 7 and 8 of the hub for a purpose to be hereinafter set forth.

In order that the propeller blades 5 and 6 maybe clamped securely to the propeller hub 1, clamping devices 16 and 17 are provided. The clamping devices 16 and 17 being of similar construction only one of the devices will be described in detail.

The clamping device 16 comprises a clamping ring composed of two semi-circular ring portions 18 and 19 of substantially inverted channel shape. Stated more specifically the semi-circular ring 18 comprises radially depending flanges 21 and 22 that are connected by a web 23.

Similarly the semi-circular portion 19 comprises radially depending flanges 24 and 25 which are connected by a web 26. The flanges of the clamping rings 18 and 19 are tapered to correspond to the tapered faces 9 and 10 of the flanges 7 and 8 of the hub and the faces 13 and 14 of the flanges 11 and 12 of the propeller blades.

Since the flanges 11 and 12 of the blades 5 and 6 are greater in diameter than the flanges 7 and 8 on the hub 1, the webs 23 and 26 of the semi-circular rings 18 and 19 will bear against and contact with the flan es of the propeller blades. Therefore, when t 1e rings are drawn together, the bases of the blades will be squeezed or compressed onto the extensions 4 of the hub.

The semi-circular ring portions 18 and 19 may be clamped together by means of bolts 27 which extend through shoulders .or bosses 28 at the ends of the rings. (See Figs. 1 and The rings may be drawn together by means of nuts 29 and locked in place by cotter pins 30 or other equivalent devices. As

the clamping rings are drawn together in this manner the bases of the propellers are drawn inwardly and tightly against the annular flanges of the hub 1 and also pressed radially inward against the extensions 4 whereby the propeller blades are securely mounted in place. The forces exerted by the clamping rings act in the direction indicated by the arrows 31 and 32. It will be apparent by inspection of the drawings that the ring portions of the clamping devices 16 and 17 take the centrifugal load imposed on the propellers when in motion.

The hub 1, shown in Figs. 1, 2 and 3, being a unitary or integral structure, may be machined in order to remove any excess metal which does not add to the strength of the hub. In this manner, a light weight hub of suflicient strength can be obtained. Also since each blade is provided with a sepa-- rate clamping device only one blade need be removed at a time, or if only one blade is in need of repair, only that blade need be removed. A dominant feature of the hub construction herein shown and described resides also 'in the fact that either one or both of the blades maybe removed without removing the hub from the. motor shaft.

In Figs. 4, 5 and 6 of the drawings a onepart hub 33 is shown. This hub is substantially similar to the hub shown in Figs. 1, 2 and 3 of the drawings with the exception that a removable splined two-part bushing 34 is provided for receiving the shaft of a motor, not shown. The splined bushing 34 comprises a tubular member 35 that extends partly through the hub and is secured in place by means of a member 36 which has screw thread engagement with the sleeve 35 and which extends into the hub from the side opposite to that from which the sleeve 35 enters the hub. The two-part splined bushing 34 may be locked against turning by means of keys 37.

In the form of construction shown in Figs. 4 to 6, inclusive, it is preferable to heat the hub before assembling the splined bushing 34 therewith, in order to secure a shrunk fit between the hub and the bushing.

The hub construction herein shown and described is a unitary structure which may be made from drop forged steel and ma chined and bored out to provide a hollow hub having such wall thickness that the re quired strength is retained. For this reason the hub is of light weight which is a desirable feature in the construction of hubs for airplane propellers. Since the hub is a unitary structure,'the propeller blades may be secured to the hub by individual or independent clamping devices such as the twopart clamping ring of inverted channel shape. In this manner each propeller blade may be mounted on the hub independently of the other and firmly and rigidly secured in place.

While various modifications and changes may be made in the propeller hub herein shown and described without departing from the spirit and scope-of the invention, it is to be understood that only such limitations shall be placed on the invention as are imposed by the prior art and the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In combination, a propeller' hub having an annular flange at each end, a propeller blade for each end of the hub, each blade having an annularflange adjacent to and abutting its corresponding flange on the hub when in operative position, and a two-part clamping ring, each part being semi-circular and of channel shape in section, for each blade for holding the flanges of the hub and the blades in firm and rigid relationship.

2. In combination, a propeller hub having a tapered annular flange at each end, a propeller blade for each end of the hub, each blade having a tapered annular flange abutting its associated hub flange, a two-part clamping ring of substantially channel shape in section embracing said hub and blade flanges for clamping the flanges of the hub and the blades in firm and rigid relation, and bolts extending through the clamping ring parts to provide the clamping force exerted by said ring parts on the hub and blade flanges.

3. In combination, a propeller hub having an annular flange and a blade receiving portion extending outwardly from said flange, a propeller blade having a sleeve at the base thereof disposed to fit over said blade receiving portion, said blade having an annular flange disposed adjacent to and abutting the flange onsaid hub when in operative position, a clamping ring including two semi-circular parts of channel shape in section for embracing and clamping the flanges of said hub and blade together, and bolts extending through the adjacent ends of said semi-circular parts for drawing the same into clamping position.

4, In combination, a propeller hub having a tapered annular flange and a blade receiving portion extending outwardly from said flange, a propeller blade having a sleeve at the base thereof disposed to fit over said blade receiving portion, said blade having a tapered annular flange abutting the flange on said hub when in operative position, including two semi-circular sections of channel shape for clamping the flanges of said hub and blade together.

5. In combinatlon, a single piece hub having a propeller shaft bore therein, circular flanges formed integrally with the hub on each side of said bore and parallel to the longitudinal axis thereof, tubular blade receiving portions extending outwardly from said hub, said tubular portions being coaxial with said circular flanges, a propeller blade mounted on each tubular portion, each blade having a socket in the base thereof for receiving its co-operating tubular hub portion, each blade havi a circular flange at the base thereof abuttmg its accompanying hub flange, and means for securing each 49 blade to the hub and taking the centrifugal load imposed on the blades when in motion, said means comprising a ring for each blade, each ring including two semi-circular parts of channel shape in section so as to embrace the abutting hub and blade flanges, and bolts for drawing adjacent ends of the semi-circular parts of each ring together to produce the clamping action required to hold the blades on the hub.

In testimony whereof, I have hereunto subscribed my name this 9th day of November, 1929.

SIDNEY T. CARTER.

CERTIFICATE OF CORRECTION Patent No. 1,865,170. June 28, 1932.

SIDNEY T. CARTER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, line 6, claim 3, strike out the word "disposed"; line 22, claim 4, after "position," insert aclamping ring; and line 24, after "shape" insert the words embracing said hub and bladeflanges, and bolts extending through the adjacent ends ofsaid semicircular sections; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office. g

Signed and sealed this 22nd day of November, A. D. 1932.

M. J. Moore, (Seal) Acting Commissioner of Patents. 

